Leaf OBC Upgrade

Background

Nissan Leafs between 2013-2017 (Gen 1.5) 24 and 30 kWh had the option of two on-board charging systems rated at either 3.3 or 6.6 kW. The cost to upgrade was £1000, and it would half the charge time if connected to a 7 kW post.

The on-board charger is situated on top of the motor-inverter block and completes the engine-like look of the Leaf. It functions as a kind of junction/distribution block for the battery and performs multiple functions:

  • AC charger, either 3.3 or 6.6 kW
  • Connection to Rapid charger port
  • 12V DC-DC (charges the 12V battery)
  • Distributes to HV water/compressor pump
  • Distributes to Motor-inverter
  • Contains contactors for all

Note 1: On the Visia models of Leaf, the rapid charger connections are not present. It is meant to be possible to swap an Acenta/Tekna 3.3 or 6.6 kW charger in place with the connectors to enable rapid charging

Note 2: This upgrade is not possible on the Gen 1 Leaf (2011-2013) as the charger was fitted in the boot and only offered at 3.3 kW speed.

Charger Swap Process

WARNING: THE CHARGER IS CONNECTED TO THE HIGH VOLTAGE (HV) SYSTEMS ON THE CAR AND SHOULD ONLY BE WORKED ON BY COMPETENT TRAINED PERSONS. ATTEMPTING ANY WORK ON THE VEHICLE IS DONE SO AT YOUR OWN RISK.

The process of swapping the on board charger is not simple. The key challenges are as follows:

  • A significant amount of trim around the wipers/glass must be removed to provide access
  • High voltage safety must be considered
  • The lid of the charger is glued, this is very difficult to pry off without damaging the aluminium casting
  • The charger is part of the coolant circuit
  • Lots of bolts in hard to reach locations
  • Charger requires 2 people to lift so as to lift straight and not bend the inverter's pins

The good bits about the job are as follows:

  • No software/configuration is needed. The car will automatically detect the swap without the need for diagnostic tools.
  • No need to lift the car
  • The coolant system doesn't need to be completely drained, just topped up with water after completion (see here for more info)

In summary the job took 6 hours to complete (including breaks). Apart from lifting the charger, the job can be completed by 1 person.

The Video

Here is a time-lapse with voice-over of the process of swapping the charger.